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Our sister brands

Seal Screws from
Automotion Components

Seal Screws from Automotion Components

Seal screws are specialised fastening components designed to provide a reliable seal against liquids, gases, and contaminants whilst maintaining the strength and functionality of a conventional fastener.
Unlike standard screws, self-sealing screws incorporate a captive O-ring beneath the head of the fastener, helping to prevent leakage and protect sensitive equipment from environmental ingress.
Seal screws are commonly used across a wide range of applications including motors, sensors, instrumentation, fuel systems, gearboxes and industrial enclosures, where maintaining a dependable seal is critical to overall system performance. Automotion Components supplies sealing screws in a variety of head styles, materials, and sizes to suit demanding industrial, engineering and defence applications.

Seal screws are commonly used across a wide range of applications including motors, sensors, instrumentation, fuel systems, gearboxes and industrial enclosures, where maintaining a dependable seal is critical to overall system performance. Automotion Components supplies sealing screws in a variety of head styles, materials, and sizes to suit demanding industrial, engineering and defence applications.

How do self-sealing screws work?

Self-sealing screws are designed and manufactured with a precision-engineered groove beneath the head of the fastener which houses a captive O-ring. As the screw is tightened, the O-ring compresses between the underside of the screw head and the mating surface to create a secure seal.
The geometry of the groove controls the amount of compression applied to the O-ring, helping to create a consistent sealing barrier whilst protecting the seal from excessive distortion. This enables the fastener to provide
bidirectional sealing protection against liquids, gases, dirt and other contaminants.
Because O-rings retain their elastic memory, self-sealing screws can often be reused multiple times, when installed correctly. Different O-ring materials are available to suit varying temperatures, chemicals and operating environments, allowing the sealing performance to be matched to the application.

Sealing Screws Options

Screws

Each screw incorporates an integral O-ring sealing system that creates a dependable seal when installed correctly, helping to protect sensitive equipment and improve assembly reliability. Available in a variety of head styles and different configurations, sealing screws can be selected to suit different installation requirements, operating environments, and application demands.

Pan Head Seal Screws

With a versatile pan head design, these screws are suitable for a wide range of industrial and engineering applications where reliable fastening and protection against contaminants is required.
Available from M2 to M10 in A2 and A4 stainless steel, they offer an excellent combination of durability and corrosion resistance.

P0170 - Pan Head Seal Screw

Phillips drive with integral O-ring groove to seal against liquids and gases. Available in M2 to M10 and A2 stainless steel, or A4 on request.

P0171 - Pan Head Seal Screw

Slotted with integral O-ring groove to seal against liquids and gases. Available in M2 to M10 and A2 stainless steel, or A4 on request.

P0171.i - Pan Head Seal Screw

Inch. Slotted with integral O-ring groove to seal against liquids and gases. Available in A2 stainless steel, or A4 on request.

P0172 - Pan Head Seal Screw

Torx drive with integral O-ring groove to seal against liquids and gases. Available in M3 to M8 and A2 stainless steel.

Cap Head Seal Screws

Cap head seal screws are ideal where higher tightening torque and secure installation are required.
Their compact cylindrical head design makes them particularly suitable for machinery, equipment housings and precision engineering applications.

P0173 - Cap Head Seal Screw

Hex socket with integral O-ring groove to seal liquids and gases out. Available in M4 to M12 and A2 or A4 stainless steel.

P0173.P2 - Cap Head Seal Screw

With locking patch. Slotted with integral O-ring groove to seal against liquds and gases Available in M2 to M10 and A2 or A4 stainless steel.

P0185 - Cap Head Seal Screw

Torx drive with integral O-ring groove to seal against liquids and gases. Available in M2 to M16 and A2 stainless steel.

Button Head Seal Screws

Button head seal screws feature a low-profile rounded head, making them suitable for applications where smooth finish and reduced protrusion are preferred. They provide effective sealing while maintaining an attractive appearance.

P0174 - Button Head Seal Screw

Hex socket with integral O-ring groove to seal liquids and gases out. Available in M3 to M12 and A2 or A4 stainless steel.

Countersunk Seal Screws

Countersunk seal screws sit flush with the mounting surface once installed, making them ideal where a flat surface finish is required. These sealing flat head screws offer both sealing protection and a streamlined appearance.

P0175 - Countersunk Seal Screw

Hex socket, with integral O-ring groove to seal against liquids and gases. Available in M3 to M10 and A2 stainless steel.

Button Head Seal Screws

Countersunk Seal Screws

P0174 - Button Head Seal Screw

Hex socket with integral O-ring groove to seal liquids and gases out. Available in M3 to M12 and A2 or A4 stainless steel.

P0175 - Countersunk Seal Screw

Hex socket, with integral O-ring groove to seal against liquids and gases. Available in M3 to M10 and A2 stainless steel.

Nuts and Washers for Sealing Screws

Automotion Components offers a range of self-sealing nuts and washers designed to prevent the ingress or escape of liquids, gases and contaminants, helping to improve assembly integrity in industrial, engineering and fluid-handling applications. Available in a variety of sizes and stainless steel grades, these products can be used alongside sealing screws to provide a complete sealing solution.

P0178 - Integral Seal Hex Nut

Self-sealing nuts with integral O-ring groove to seal against liquids and gases. Available in M2 to M16, and A2 or A4 stainless steel.

P0179 - Integral Seal Domed Nut

Self-sealing domed nuts with integral O-ring groove to seal against liquids and gases. Available in M3 to M16, and A2 or A4 stainless steel.

P0180 - Seal Washer

Seal washers - to seal against liquids and gases. For threads M3 to M12, A2 stainless steel.

P0181 - Waterproof Seal Washer

Stainless steel, AISI 304, seal washer with thermoplastic elastomer (TPE) insert. For watertight applications.

Advantages of using Self-Sealing Screws

Self-sealing screws offer several advantages over conventional fastening methods where environmental protection is required:

Provides bidirectional sealing against liquids, gases, dirt and contaminants.

Eliminates the need for separate sealing compounds in many applications.

Quick and straightforward to install; counterbore needed.

O-ring design helps maintain consistent sealing.

Reusable when correctly installed and maintained.

Available with choice of O-ring materials for varying environmental conditions.

Suitable for demanding industrial, medical, military and engineering applications.

Helps protect sensitive equipment and reduce the risk of contamination or leakage.

Self-sealing screws offer several advantages over conventional fastening methods where environmental protection is required:

Provides bidirectional sealing against liquids, gases, dirt and contaminants.

Eliminates the need for separate sealing compounds in many applications.

Quick and straightforward to install; counterbore needed.

O-ring design helps maintain consistent sealing.

Self-sealing screws offer several advantages over conventional fastening methods where environmental protection is required:

Provides bidirectional sealing against liquids, gases, dirt and contaminants.

Eliminates the need for separate sealing compounds in many applications.

Quick and straightforward to install; counterbore needed.

O-ring design helps maintain consistent sealing.

Reusable when correctly installed and maintained.

Available with choice of O-ring materials for varying environmental conditions.

Suitable for demanding industrial, medical, military and engineering applications.

Helps protect sensitive equipment and reduce the risk of contamination or leakage.

Reusable when correctly installed and maintained.

Available with choice of O-ring materials for varying environmental conditions.

Suitable for demanding industrial, medical, military and engineering applications.

Helps protect sensitive equipment and reduce the risk of contamination or leakage.

Sealing Screw Heads

Drive Types

Sealing screws are available with a variety of drive types to suit different installation methods, torque requirements and security needs. The table below outlines the common drive configurations available and their typical uses, helping engineers and procurement teams select the most suitable fastening solution for their application.

Schematic	Drive Types	Uses
	Hexagonal	Ideal for precision assembly. Most recommended where less surface area is available.
	Cross Drive (Phillips®)	Most recommended drive type. Provides good control in driving. Always use a driver bit of the proper size which is in good condition.
	Star Drive (Torx®)	Positive-engaging, fast-locating method which transmits drive torque with less required downward pressure. Good fastening appearance.
	Slotted	Accepts standard blade screwdriver. Requires less downward pressure to drive parts than those with recessed openings. Use proper fitting blade to minimize slippage.
	Hex flange	Accepts hex wrench. Slotted drive is added to make it easier to remove the fastener (if required).
	Security	These screws are impossible to remove without the special matching screwdriver.

We can provide Torx® heads and security/tamper-proof screws, as well as special threads, grooves and cross holes for safety wires, and a further range of styles such as captive screws, anti-vibration strips on the threads etc (for extreme vibration applications).

Applications

Some of the typical applications for our sealing screws include:

Motors
Cabinets and enclosures
Sensors and instrumentation
Internal combustion engines
Gear pumps

Fuel tanks
Transmissions
Gear boxes
Air cylinders
Pressure gauges

Computer disk drives
Motion control valves
Missile tanks
Wet wings

Technical Specs

O-ring selection

Standard O-rings are red silicone, but a further five O-ring material types are readily available. The main factor to consider when selecting an O-ring type is the environment in which it will be placed, and the temperature range it will be subjected to.

Material	Notes
Silicone (SI)	Our standard O-ring type with a wide temperature range -60°C to +200°C. Resistant to moderate or oxidising chemicals, but not generally oil or solvent resistant.
Fluorosilicone (FS)	Widely used in the automotive and aerospace industries as it has excellent resistance to fuel, oil and solvents. Standard temperature range -50°C to +180°C.
EPDM (EP)	These O-rings are very suited for outdoor environments and are good for weather and water resistant applications having excellent ozone, steam and chemical resistance. Temperature range -50°C to +110°C.
Viton-fluorocarbon (VI)	These seals are widely used on aircraft engines and automotive fuel handling systems as they have excellent fuel, oil and solvent resistance. Standard temperature range -50°C to +100°C.
Nitrile (NI)	Widely used as highly resistant to petroleum-based substances, water and alcohols. Temperature range -50°C to +110°C.

Other O-ring types can include Neoprene, Buna N, PTFE etc.

Installation Torque for Seal Screws

diagram with labels on installation torque for sealing screws

Thread Size	Standard Installation Torque
M 3	0.6 Nm
M 3.5	1.0 Nm
M 4	2.2 Nm
M 5	2.5 Nm
M 6	8.5 Nm
M 8	16 Nm
M 10	30 Nm

For optimal seal screw performance, we recommend creating a clearance gap in the panel into which the O-ring can be fitted. This causes the O-ring to create a complete seal, and the clearance hole thus prevents extrusion into the metal when the screw is under pressure.
We also have a range of sealing nuts to complement our range of sealing screws. These sealing nuts often eliminate the need for gaskets, compounds and surface preparation. They are widely used in the hydraulic, pneumatic or fuel systems industries. They are invaluable when a vacuum needs to be created and provide a complete seal when gases or liquid pressure is a factor. Domed nuts are self-sealing and provide exceptional vibration resistance.

Clearance Hole Ø - A Necessity

Nom. Size

Max

2,437

M2.5

2,946

3,454

M3.5

3,656

Nom. Size

Max

4,546

5,562

6,655

9,041

Nom. Size

Max

M10

11,048

M12

14,048

M14

16,051

M16

18,057

Nom. Size

Max

M 2

2,437

M 2.5

2,946

M 3

3,454

M 3.5

3,656

M 4

4,546

M 5

5,562

Nom. Size

Max

M 6

6,655

M 8

9,041

M 10

11,048

M12

14,048

M14

16,051

M16

18,057

diagram with labels of a clearance hole for sealing screws

Materials

Automotion Components' sealing screws are supplied as standard in A2 stainless steel (AISI 303), offering an excellent balance of strength, corrosion resistance, and durability for a wide range of industrial applications.
We offer a range of materials to meet specific environmental, weight or performance requirements, as A4 stainless steel (AISI 316) for enhanced corrosion resistance in demanding environments. Fasteners can also be supplied to military specifications on request, such as blackened finish.

Finishes

A variety of finishes are available depending on the selected material and application requirements. These include black chrome, black oxide, cadmium, passivation, phosphate coating, gold, nickel and zinc finishes. Each option offers different benefits relating to appearance, corrosion resistance, wear protection and environmental performance.

Finish	Notes
Black Chrome (MIL-C-1458B)	Black chrome is hard, non-reflective coating which is resistant to abrasion, heat and erosion. The black chrome surface is a dull, dark grey and may be waxed or oiled to darken surface.
Black Oxide Coating (MIL-C-13924B)	Black oxide is a uniform black coating for ferrous metals. Generally it is considered a decorative coating and provides only very limited corrosion protections under mild corrosion conditions.
Cadmium	Cadmium is a bright, silvery white plating. Supplementary treatments for type II can be golden, iridescent, amber, black or olive drab.
Passivate (QQ-P-35/MIL S-5OOSC)	Passivation is a process designed to remove foreign metals from the surface of stainless and corrosion resistant steels.
Phosphate Coating Light (TT-C-00490B)	Phosphate coating is a light coating for use as a base paint.
Gold (MIL-G-45204B)	Yellow to orange colour depending on a proprietary process used. Will range from matt to bright finish depending on base metal. Good corrosion resistance and high tarnish resistance.
Nickel	Nickel is a corrosion protective plating for steel, zinc and zinc alloys as well as copper and copper alloys.
Zinc (QQ-Z-325C)	The primary use of chromate finishes on zinc is to retard or prevent formation of white corrosion products on zinc surfaces.

Frequently Asked Questions About Self-Sealing Screws

What are the benefits of Sealing Screws?

Sealing screws provide reliable protection against the ingress or escape of liquids, gases and contaminants while also performing the structural role of a conventional fastener. Their integrated O-ring design can reduce the need for additional sealing materials, simplify assembly and help improve the reliability of sensitive equipment.

Are Sealing Screws safe?

Yes. When correctly specified and installed, sealing screws provide a secure fastening solution while maintaining a dependable environmental seal. They are widely used in industrial, defence, medical and engineering applications where protection from contamination or leakage is important.

How to Buy Sealing Screws

Automotion Components offers a wide range of screw seals, sealing nuts and sealing washers in
multiple sizes, materials and configurations. Browse the available product ranges above to review
technical specifications, download our CAD files or contact our technical team for assistance selecting the most suitable fastener for your application.